Mechanism of stress relaxation in (0001) InGaN/GaN via formation of V-shaped dislocation half-loops

From the analysis of available experimental data, we suggest a mechanism of stress relaxation in strained (0001) InGaN/GaN layers, assuming formation of V-shaped edge-type dislocation half-loops. An energy-balance approach is applied to estimate the critical thickness of the InGaN layer resulting in generation of the V-shaped half-loops. The computed dependence of the critical thickness on the InGaN composition agrees well with the literature data reported for single-layer InGaN/GaN heterostructures.